1. Field of the Invention
This invention relates generally to gold concentrators, including dredgers and high-bankers used in placer mining, and more particularly to a staged sluice for increment size classification and ore extraction.
2. Prior Art
The prior art in placer mining techniques discloses a large number of various devices sometimes termed collectors, separators, or extractors but all directed to extracting small amounts of gold from large volumes of mineral matter. It is known that the majority of gold in placer deposits is fine and very fine grain ore, the larger part of which is typically uncaptured in prior extraction techniques. Though all of the techniques seek to exploit the high specific gravity of gold, the difficulty of removing ore from the matrix in which it is found rests in overcoming detrimental effects of physical forces acting on such fine particles, such as suspension action in a slurry of the matrix in water and surface tension. These effects are exacerbated when fine ore competes with action of larger mineral aggregates, and separation and settling of ore due to its higher specific gravity is defeated. Therefore, the preliminary task before separation by specific gravity is first classification of the matrix and ore by size until ore and gangue can compete in terms of relative specific gravity with minimal effects, or at least non-dominating effects of other physical forces.